Why doesn't UNION of queries that return X and Y records return X+Y records?
This is because UNION only returns unique records, i.e. if the same row is found in both result sets, it will be shown only once in UNION. It you wish to have all the rows use UNION ALL instead.
Do you find this FAQ incorrect or incomplete? Please e-mail
needs to be changed. To ensure quality, each change is checked by our editors (and often tested on live Firebird
databases), before it enters the main FAQ database. If you desire so, the
changes will be credited to your name. To learn more, visit our add content
If you are a commercial tool maker and your tool features a great way to handle
the issue written about in this FAQ, please check out our advertisement
All contents are copyright © 2007-2021 FirebirdFAQ.org unless otherwise stated in the text.